Optically initiated devices to achieve detonations have been developed and used following the evolution of laser technology. These types of optically initiated devices employing coherent laser light are referred to as laser activated devices.
One common practice used in laser actuated devices is to form a glass-to-metal seal in which the glass (or quartz) is optically clear and acts as a window to the coherent laser light. Pyrotechnics or explosives are pressed or coated onto one side of the glass surface and are initiated by the energy of a laser beam which passes through the glass. When using detonable materials such as hexanitrostilbene (HNS), cyclotrimethylenetrinitramine (RDX), pentaerythritol tetranitrate (PETN), and others, the explosive force generated fractures the window. If such a device is used in a pressurized application such as a rocket motor, the fracture of the window may result in a hot gas leak that would lead to catastrophic failure of the rocket.
Thus, when a laser actuated device is employed in a pressurized application, such as a rocket motor, it is essential that primary and secondary explosives may be used without causing damage to the window passing the coherent laser light.
The primary object of this invention is to provide an optical path from a laser source to an active explosive material, wherein a portion of the material in this path is composed of materials which absorb or attenuate the shock of the explosive without damaging the primary glass window and pressure seal.
A further object of this invention is to provide an optically actuated device wherein a detonating material is employed to initiate a deflagration reaction and an absorbing medium is employed in combination with the device to protect the window and pressure seal from damage.